Method of construction of electric motors.



Patented lan. 22, 190|.

No. 666,3l5.

F. .JOHNSON.

METHOD 0F CONSTRUCTION'UF ELECTRIC MOTORS.

(Applicmifml n led Aug. so, 1900.)

(No Model.)

SH01/u m a UNITED STATES PATENT OEEICE.

FREDERIC AYRES JOHNSON, OF BINGIIAMTON, NEW YORK, ASSIGNOR TO THE STOWMANUFACTURING COMPANY, OF SAME PLACE.

METHOD OF CONSTRUCTION OF ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 666,315, dated January22, 1901.

Application led August 30, 1900. Serial No. 28,550. (No model.)

To @ZZ whom, it may con/cern:

Be it known that I, FREDERIC AYREs J OHN- SON, a citizen of the UnitedStates, residing at Binghamton, Broome county, State of New York, haveinvented certain new and useful Improvements in Methods of Constructionof Electric Motors, of which the following is a specification.

My invention relates to means for controlling electric motors, and hasfor its object to provide a simple and effective means for accomplishingthis result; and it consists in the various features of construction andarran gement of parts, having the mode of operation substantially ashereinafter more particularly set forth.

Referring to the accompanying drawings, Figure l is a verticaltransverse section through a motor embodying my invention, and Fig. 2 isa vertical longitudinal section of the same.

While my invention is intended more particularly for use in connectionwith electric motors, it can be used with electric generators. It isbased on the general principles set forth in my Patent No. 597,418,granted January 18, 1898, and I do not deem it necessary herein toexplain those principles nor to set forth fin ctenso the advantages ofthis general method of speed regulation for motors.

While my invention can be applied to motors of various forms andconstructions, I have chosen to show it in connection with a very simpleform wherein there is but a single exciting-coil, and this willillustrate the invention sufficiently to enable those skilled in the artto adapt it to the particular form of motor or generator desired.

Referring to the drawings, A represents the armature, which may be ofany desired form and construction and is provided with the usualappurtenances, and B represents the held-magnet, it being shown in thepresent instance in the form of a rectangular frame having pole-pieces CC', and the latter are formed integral with the frame, and the armatureis'supported in bearings A A2, connected to the frame, and the wholeforms an inolosed or iron-clad motor. If desired, a Switch S can bearranged on the interior of the frame, as shown in Fig. l, operated bythe switch-arm SQ projecting through the frame, and in this way all theoperative parts of the motor and the switch controlling the circuitsthereof are inclosed and protected.

i In the present instance the pole-piece C is supplied with afield-magnet coil D, surrounding the neck or reduced portion of thepolepiece, and the pole-piece is made detachable from the frame, so thatthe coil can be slid over the neck. In the present instance the frame isprovided with an opening B', through which a reduced portion C2 of theneck eX- tends, and this portion is provided with some .suitable meanswhereby the pole-pieee can be secured in position, it heilig shown asscrewthreaded at c, and there is a cup-shaped nut E, having an internalscrew-thread e engaging the reduced portion of the neck of thepolepiece, and by this means the pole-piece can be securely held inproper position.

In order to prevent the pole-piece from turning and to keep it in properalinement, I provide some suitable means-as, for instance, dowel-pinsl), mounted in the inner portion of the frame B and engaging dowelholesin the neck of the pole-piece; but any other mechanical means may beutilized to insure the proper relation of the pole-piece to thearmature.

The reduced portion C2 of the neck is hollow, and mounted therein is ablock F of magnetic material capable of sliding therein, and some sortof means are provided for preventing its rotation when the block iscylindrical, and to accomplish this in the present instance l provide alongitudinal keywayor slot f, int-o which extends a pin or projectionf', which permits the block or plunger to move longitudinally, butprevents rotation therein.

Some suitable means should be provided for adjusting the block orplunger in the pole-piece, and while various means may be used I haveshown a screw-bolt G, secured to the end of the block or plunger, as bya pin g, and this bolt passes through the cupshaped nut E and in thepresent instance is provided with an eye G'. Engaging the bolt is ahand-wheel or nut H, bearing on the cupshaped nut, and it is manifestthat by ad- ICO justing this hand-wheel the block or plunger can beadjusted in the hollow portion of the neck of the pole-piece.

This being the preferred construction, the mode of assembling andoperating my device will be largely understood from what has preceded,and it will be seen that the block or plunger F can be adjusted so as tovary the magnetic flux passing through the armature, and at the sametime the flux through the tips of the armature will not be variedmaterially, so that there will be no danger from sparking. It isunderstood, of course, that the speed of the motor, other things beingequal, depends upon the number of lines of force or amount of magneticHnx passing through the armature, and when the block or plunger is inthe position shown under a constant-potential current the maximum fluxis passing. IVhen, however, the block or plunger is raised, the fluxthrough the center of the pole-piece is reduced and the speed of themoter is increased, while the flux through the polar tips is maintainedsubstantially constant, so that the commutated coils lare still in astrong field, avoiding sparks.

Vliile I have shown but one field-magnet core arranged and constructedas above described, it is manifest that other cores in a multiple-coremotor may be similarly constructed and arranged.

Having thus described the preferred embodiment of my invention, it willbe evident that the speciiic means may be varied, and without limitingmyself to the precise details shown what I claim isl. In an electricmotor, the combination with the, frame, of a eld-magnet pole having ahollow reduced neck, a coil around said neck and means for detachablyconnecting the pole to the frame, substantially as described.

2. In an electric motor, the combination with the frame, of aheld-magnet pole having a reduced neck, the frame havingan openingthrough which the neck is passed, and a nut engaging the neck supportingand securing the same to the frame, substantially as described.

3. In an electric motor, the combination with the frame having anopening, of a fieldmagnet pole the neck of which is provided with areduced screw-threanled portion passing through the opening in theframe, and a cup-shaped nut engaging the reduced portion for securingthe pole in place, substantially as described.

4. In an electric motor, the combination with the frame having anopening, of a hollow held-magnet pole detachably connected thereto, ablock mounted in the hollow neck of the pole-piece, and means foradjusting the block therein, substantially as described.

5. In an electric motor, the combination with the frame having anopening, of a hollow field-magnet pole detachably connected thereto,acup-shaped nut engaging the neck of the pole-piece to secure the same inposition, a plunger moving in the hollow neck,a bolt secu red to theplunger, and a hand-wheel engaging the bolt for adjusting the pl ungcr,substantially as described.

G. In an electric motor, the combination with the frame having anopening, of a fieldniagnet pole having a hollow neckextending throughthe opening, a cup-shaped nut for securing the pole in position, aplunger fitting the holiow neck, means for preventing rotation of theplunger therein, a bolt engaging the plunger-,and means for adjustingthe bolt, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FREDERIC AYRES JOHNSON.

W'itnesses:

D. S. RICHARDS, R. B. RICHARDS.

